package 网络编程.客户端与服务器的请求与响应.TCP流.服务器;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.ServerSocket;
import java.net.Socket;
import java.nio.charset.StandardCharsets;
import java.util.Scanner;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

public class TcpEchoServer {
    private ServerSocket serverSocket = null;
    public TcpEchoServer (int port) throws IOException {
        serverSocket = new ServerSocket(port);
    }
    public void start() throws IOException {
        System.out.println("启动");
        ExecutorService pool = Executors.newCachedThreadPool();//可以扩容的线程池

        while(true){
            Socket clientSocket = serverSocket.accept();
            pool.submit(new Runnable(){
                @Override
                public void run() {
                    try{
                        processConnection(clientSocket);
                    } catch (IOException e){
                        e.printStackTrace();
                    }
                }
            });
        }

    }
    private void processConnection(Socket clientSocket) throws IOException {//连接
        System.out.printf("[%s:%d] 客户端上线!\n", clientSocket.getInetAddress(), clientSocket.getPort());
        try(InputStream inputStream = clientSocket.getInputStream();
                OutputStream outputStream = clientSocket.getOutputStream()) {
            Scanner sc = new Scanner(inputStream);
            while(true){
                if(!sc.hasNext()){
                    System.out.printf("[%s:%d] 客户端下线!\n", clientSocket.getInetAddress(), clientSocket.getPort());
                    break;
                }
                String request = sc.next();
                String response = process(request);
                outputStream.write(response.getBytes(),0,response.getBytes().length);
                System.out.printf("[%s:%d] req=%s, resp=%s\n", clientSocket.getInetAddress(), clientSocket.getPort(), request, response);
            }
        } catch (IOException e) {
            throw new RuntimeException(e);
        }finally{
            clientSocket.close();
        }
    }

    private String process(String request) {
        return request + "\n";
    }

    public static void main(String[] args) throws IOException {
        TcpEchoServer server = new TcpEchoServer(9090);
        server.start();
    }
}
